The invention relates to an integrated circuit arrangement for current regulation of an electromagnetic load.
Such circuit arrangements have been known for a long time for controlling electric motors, generators, solenoid valves, or the like and have also been in practical use. The use of such circuits for regulating the charging of automobile batteries during motor and generator operation shall be mentioned merely as one example.
For such circuit arrangements, which are also designated as “clocked systems” and which are essentially composed of a coil, a power switch, and a freewheeling diode, an exact measurement of the coil current represents an important technical problem. This current measurement is usually performed by using a measurement resistor (the shunt), which is external or also internal to the circuit and whose voltage drop is fed to a measurement amplifier.
For this measurement principle, the small magnitude of the voltage drop on the shunt on the one hand and large common mode jumps on the amplifier input (caused by the transitions between battery voltage and negative voltages in the freewheeling case) on the other hand represent a technical problem, which has heretofore prevented the realization of shunt systems from operating completely satisfactorily.